Troubleshooting a nukular oven that no longer heats
#1
Troubleshooting a nukular oven that no longer heats
My mom's microwave oven stopped heating. It looks to be working normally -- display, lights, turntable, exhaust fan -- but nothing gets hot. It's a Hamilton Beach from Wally World.
The magnetron still looks new, no signs that the smoke has escaped. I tested it with my el-cheapo Craftsman DMM and I get OR from either post to the outer case, and 10-ish Ohms between the posts. Dr. YouTube says this means the magentron isn't burned out (but I struggle to diagnose a burned-out light bulb). The thermal fuse, OTOH, tests 40-ish Ohms.
Does this sound like a bad thermal fuse to you? I've checked ebay and I can replace it for less than $10. Is there any harm in reassembling the mike, shorting across the thermal fuse and (briefly) testing it to confirm the fuse in fact is the cause?
The magnetron still looks new, no signs that the smoke has escaped. I tested it with my el-cheapo Craftsman DMM and I get OR from either post to the outer case, and 10-ish Ohms between the posts. Dr. YouTube says this means the magentron isn't burned out (but I struggle to diagnose a burned-out light bulb). The thermal fuse, OTOH, tests 40-ish Ohms.
Does this sound like a bad thermal fuse to you? I've checked ebay and I can replace it for less than $10. Is there any harm in reassembling the mike, shorting across the thermal fuse and (briefly) testing it to confirm the fuse in fact is the cause?
#2
The magnetron filament should be around 1 ohm.
If the thermal fuse measures 40 ohms it's bad.
A thermal fuse is a fuse which should measure close to 0 ohms.
Typically.... the thermal fuse, if bad, will cause the entire unit to be dead.
The fuse should be a 15A or 20A white ceramic type.
There are several parts that can cause no heat.
Magnetron
High voltage transformer
High voltage capacitor
High voltage diode.
If the thermal fuse measures 40 ohms it's bad.
A thermal fuse is a fuse which should measure close to 0 ohms.
Typically.... the thermal fuse, if bad, will cause the entire unit to be dead.
The fuse should be a 15A or 20A white ceramic type.
There are several parts that can cause no heat.
Magnetron
High voltage transformer
High voltage capacitor
High voltage diode.